Preferred SIM for SMS changes randomly from desired SIM 1 to undesired SIM 2

Summary

The default SIM for SMS is regularly reset to SIM 2 although I want SIM 1. Calls and mobile data meanwhile keep their correct value. I'm regularly changin country. In the first one SIM 1 is in local and SIM 2 in roaming, in the second SIM 1 is roaming and SIM 2 is local. I didn't test if the bug is related.

Steps to reproduce

Set SIM 1 as default for SMS. I'm using smsmatrix, a sms-matrix bridge that can be installed from F-Droid

What is the current behavior?

After undetermined amount of time or after undetermied event, SIM 2 is set as default for SMS Tests:

• After reboot, default SIM is set to 2 => not reproducible (1 time over 3)
• After lauching smsmatrix service, default SIM remains 1 (no pb)

What is the expected correct behavior?

Default card for SMS remains SIM 1 whatever happens

Relevant logs and/or screenshots

none

Possible fixes

I'm using smsmatrix, a sms-matrix bridge that can be installed from F-Droid. I could try to uninstall and see if the issue still happens.